What are spider angiomas? Why are they associated with liver disease?
- Spider angiomas (nevus araneus) are vascular lesions characterized by a central arteriole and horizontal radiating thin-walled vessels that produce the legs of the vascular spider.
- The pulsation of the central, vertically oriented arteriole in larger lesions can be visualized with diascopy (observing the lesion through a glass slide firmly pressed on the lesion).
- The pathophysiologic mechanism is not proven, but the high incidence of spider angiomas in alcohol-associated hepatitis and pregnancy suggests that elevated levels of estrogens resulting from higher production or decreased metabolism is responsible.
- Patients with liver cirrhosis and spider angiomas have elevated plasma levels of vascular endothelial growth factor, which may play a role in the development of spider angiomas.
